consultar_cest

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The description discloses that the tool behaves in offline mode by reading from a bundled SQLite database and warns that the data may be incomplete, with instructions to run a script to populate the full table. This gives the agent a clear expectation of potential data limitations and the read-only nature of the operation, though it does not explicitly confirm absence of side effects.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description contains repeated ideas (the purpose is stated twice) and mixes English labels ('Purpose') with Portuguese content, making it a bit unstructured and slightly verbose. However, it remains readable and covers necessary points without excessive bloat.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The description covers the tool's purpose, when to use it, its offline behavior, a warning about potential incomplete data, and the input format. Since an output schema is present, the lack of output details is acceptable, making the description sufficiently complete for the tool's context.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The parameter 'cest' is fully described in the input schema, including the 7-digit format and example with punctuation. The tool description repeats this information but does not add additional nuance beyond what the schema already provides, so the description adds no extra value for parameter understanding.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool's function: to consult the CEST code and identify products subject to ICMS tax substitution, referencing the specific legal basis (Convênio ICMS 92/2015). This is specific and leaves no ambiguity about what the tool does.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description explicitly provides a usage guideline: 'Quando usar: ao emitir NF-e com produtos sujeitos ao ICMS-ST' (When to use: when issuing NF-e with products subject to ICMS-ST). This directly tells the agent when to invoke this tool, which is highly actionable.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.